Mattress protector



FIG. 1 is a top plan view of a mattress protecor, showing my new design;

FIG. 2 is a cross-sectional view taken along line 2—2 in FIG. 1; and,

FIG. 3 is a cross-sectional view taken along line 3—3 in FIG. 1.

The broken lines are for environmental purposes only and form no part of the claimed design. 

The ornamental design for a mattress protector, as shown and described. 